doesn't it work to just cut your highlights from "my clippings", paste them somewhere else and by this removing the highlights from the kindle? doesn't this open up new highlighting options?

My Clippings is a log file, it's not where the highlights are stored and tracked (that's done in a .mbp or .tan 'sidecar' file).

But after creating a set of highlights, you can delete them, and create a new set (probably, unless the maxhighlights count never decreases). My clippings will capture all of the highlights you made over the course of things. But of course this means the actual book will only show the current set, which kind of defeats the purpose.